Technical Field
The present disclosure relates to a liquid crystal display device, including a liquid crystal display device with a liquid crystal capsule layer.
Discussion of the Related Art
Recently, with the rapid progress of the information age, there is an increasing demand for various types of display devices. For example, various flat panel displays (FPDs) such as a liquid crystal display (LCD) device, a plasma display panel (PDP), a field emission display (FED) device and an organic light emitting diode (OLED) display devices have been researched. Since FPDs have advantages such as a thin profile, light weight and low power consumption, cathode ray tube (CRT) devices have been widely replaced with FPDs.
Among various FPDs, an LCD device has various features such as a high contrast ratio and a superior moving image display capability. LCD devices have been widely used, such as in computer monitors or televisions.
FIG. 1 is a cross-sectional view illustrating a liquid crystal display device according to the related art.
As shown in FIG. 1, a related art liquid crystal display (LCD) device 10 includes a liquid crystal panel and a backlight unit 60 under the liquid crystal panel. The liquid crystal panel includes first and second substrates 2 and 4 and a liquid crystal layer 50 between the first and second substrates 2 and 4.
A thin film transistor (TFT) Tr on an inner surface of the first substrate 2 includes a gate electrode 12, a gate insulating layer 13, an active layer 14, ohmic contact layers 15a and 15b, a source electrode 16 and a drain electrode 17. The drain electrode 17 is connected to a first electrode 19 in a pixel region P through a contact hole in the interlayer insulating layer 18.
A black matrix 32 surrounding the pixel region P is formed on an inner surface of the second substrate 4 to block a non-display element such as the TFT Tr of the first substrate 2 and to expose the first electrode 19. In addition, a color filter layer 34 corresponding to the pixel region P is formed in the black matrix 32. The color filer layer 34 has a lattice shape, and overlaps with an edge of the black matrix 32. A second electrode 36 is formed on the black matrix 32 and the color filter layer 34.
Polarizing plates 20 and 30 transmitting a selected polarization component are formed on outer surfaces of the first and second substrates 2 and 4, respectively.
A first alignment layer 31a is formed between the first electrode 19 and the liquid crystal layer 50, and a second alignment layer 31b is formed between the second electrode 36 and the liquid crystal layer 50. The first and second alignment layers 31a and 31b determine an initial alignment state and an initial alignment direction of the liquid crystal molecules in the liquid crystal layer 50.
A seal pattern 70 is formed at an edge portion between the first and second substrates 2 and 4 to prevent leakage of the liquid crystal layer 50.
Since the LCD device 10 is not an emissive device, the additional backlight unit 60 disposed under the liquid crystal panel provides light to the liquid crystal panel.
The liquid crystal layer 50 includes one of a nematic liquid crystal, a smectic liquid crystal and a cholesteric liquid crystal.
In the related art LCD device 10, after the TFT Tr and the first electrode 19 are formed on the first substrate 2 and the color filter layer 34 and the second electrode 36 are formed on the second substrate 4, the first and second substrates 2 and 4 are attached to each other. Since an additional alignment process is required to attach the first and second substrates 2 and 4, the corresponding fabrication process is complicated and the fabrication cost increases.
In addition, an alignment process including a printing step and a rubbing step of the alignment layers 31a and 31b is required for aligning the liquid crystal molecules. As a result, the production yield is reduced.
Further, after the liquid crystal molecules are injected into the attached first and second substrates 2 and 4, the first and second substrates 2 and 4 have to be kept spaced apart from each other by a uniform gap. When the gap between the first and second substrates 2 and 4 is changed by an external pressure or an external impact, the display quality of the LCD device 10 deteriorates.